1. Field of the Invention
The present invention relates to the transport of articles, for example during a packaging procedure, and particularly to elimination of variations in the loading of endless-belt type conveyors. More specifically, the present invention relates to a belt conveyor and especially to a conveyor for use in a cigarette packaging machine wherein partially wrapped blocks of cigarettes are received in spaced cells or carriers supported on the belt and the belt is guided around a driven wheel and a second spacially displaced wheel. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited for use on cigarette-packaging machines. It is common practice in the cigarette packaging industry to employ belt conveyors which carry equidistantly spaced cells, the cells each defining a cuboid space which receives, for example, a block of cigarettes which has been formed and subsequently wrapped in an inner paper. The belt conveyors on cigarette-packaging machines are typically guided around a pair of wheels which are spaced from one another by a significant distance, one of the wheels being driven and the other being an idler wheel. Since a cigarette packaging process proceeds in step-wise fashion, the driven wheel over which the belt passes is typically energized, via drive shaft, in steps which are commensurate with one or more cell divisions. In some instances, of course, the belt may be driven continuously. In either case, it is common practice, in the region of the upper and/or lower strands of the belt, for the cells to be guided by rails. At the points where the direction of the belt changes, i.e., at the drive and idler wheels, the cells will typically be engaged by recesses provided on the circumference of the wheels.
A problem of long-standing in the art is presented by the fact that the use of a single drive wheel subjects the belt to uneven loading, this being particularly true with respect to the belt tension in front of the drive wheel and to the force applied to the belt downstream of the drive wheel in the direction of transport. With short cycle time and relatively long belt lengths, which are both customary operating conditions on cigarette-packaging machines, the aforementioned variations can have an adverse effect on, for example, the positioning of the cells in the regions where the contents thereof are to be received from or transferred to cooperating conveyors.